This invention relates to a group of novel aromatic polyamides having 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane derivative units and a method of preparing same. The novel polyamides are excellent in heat resistance and soluble in various organic solvents.
Aromatic polyamide resins are generally excellent in mechanical characteristics such as tensile strength, elastic modulus and impact resistance, thermal characteristics such as heat distortion temperature and thermal decomposition temperature, dielectric characteristics, flame resistance and radiation resistance. In particular the aromatic polyamides disclosed in JP 35-13247 possess superior properties which have offered prospects for industrial applications. However, practical applications of these polyamides have been limited because of very poor solubilities in organic solvents.
Even though a polymer possesses attractive properties the polymer is of little value as an industrial plastic material unless it has good melt-processability and/or good solubility in a solvent low in price and convenient for industrial use. Considering high melting or softening temperatures of known aromatic polyamides, there is little expectation of aromatic polyamides very suitable for melt processing. Besides, solution coating processes cannot always be substituted by melt processing.